Tapering for Marathon and Cardiac Autonomic Function

Abstract The purpose of this study was to investigate changes in post-exercise heart rate recovery (HRR) and heart rate variability (HRV) during an overload-tapering paradigm in marathon runners and examine their relationship with running performance. 9 male runners followed a training program composed of 3 weeks of overload followed by 3 weeks of tapering (−33±7%). Before and after overload and during tapering they performed an exhaustive running test (T lim ). At the end of this test, HRR variables (e.g. HRR during the first 60 s; HRR 60 s ) and vagal-related HRV indices (e.g. RMSSD 5–10 min ) were examined. T lim did not change during the overload training phase (603±105 vs. 614±132 s; P=0.992), but increased (727±185 s; P=0.035) during the second week of tapering. Compared with overload, RMSSD 5–10 min (7.6±3.3 vs. 8.6±2.9 ms; P=0.045) was reduced after the 2 nd week of tapering. During tapering, the improvements in T lim were negatively correlated with the change in HRR 60 s (r=−0.84; P=0.005) but not RMSSD 5–10 min (r=−0.21; P=0.59). A slower HRR during marathon tapering may be indicative of improved performance. In contrast, the monitoring of changes in HRV as measured in the present study (i.e. after exercise on a single day), may have little or no additive value.